[POWERPC] Fix pci_setup_phb_io_dynamic for pci_iomap

We had a problem on a system with only dynamically allocated
PCI buses (using of_pci_phb_driver) in combination with libata.
This setup ended up having no "primary" phb, which means
that pci_io_base never got initialized and all IO port
numbers are 64 bit numbers, which is larger than the
PIO_MASK limit.
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/of_platform.c

@@ -433,7 +433,7 @@ static int __devinit of_pci_phb_probe(struct of_device *dev,
 	 * Note also that we don't do ISA, this will also be fixed with a
 	 * more massive rework.
 	 */
-	pci_setup_phb_io(phb, 0);
+	pci_setup_phb_io(phb, pci_io_base == 0);
 
 	/* Init pci_dn data structures */
 	pci_devs_phb_init_dynamic(phb);